The present invention relates to identification card printers. More specifically, the present invention relates to monitoring operation of identification card printers.
Printers are complex electro-mechanical devices that use multiple continuous and discrete processes for the transfer of an image or text to a media. Plastic ID card printers utilize multiple processes for the feeding, transport, encoding, thermal printing, lamination and stacking of plastic cards.
Plastic ID card printers can be broken into several simple process control loops each of which include an actuation device, a measurement and a controller. The actuation devices and the sensors are electromechanical devices prone to failure. The failure of a single device renders the printer inoperable. Typical actuation devices used as the final control device in a plastic ID card printer include: stepper motors, continuous motors, solenoids, clutches, cutting devices, fans, and encoding/reading devices for magnetic stripes, proximity transceiver programming, and smart card encoding. Sensors for measuring loop parameters will include: temperature sensors e.g. thermocouples, RTD""s, thermister and diodes, position sensors and encoders, force sensors, current and voltage sensing circuits, switches for position or the presence of a card, magnetic stripe readers, velocity or rotational velocity etc.
Diagnostic and event monitoring techniques have been used in other industries such as industrial process control. For example, U.S. Pat. No. 6,017,143, entitled DEVICE IN A PROCESS SYSTEM FOR DETECETING EVENTS, which issued Jan. 25, 2000 shows such a system.
An identification card printer for printing an identification card includes a print mechanism configured to print onto the identification card. A process signal input is configured to receive a process signal related to operation of the identification card printer. A memory contains a nominal process signal statistical parameter and a rule. A microprocessor is coupled to the memory and configured to receive the process signal from the process signal input and calculates a statistical parameter of the process signal. The microprocessor compares the calculated statistical parameter to the nominal statistical parameter based upon the rule and responsively provides an event output as a function of the comparison. The event output is related to an occurrence of an event during operation of the identification card printer.